Tapping machine



y 11, 1939- J. H. MANSFIELD TAPPING MACHINE Filed March 15, 1935INVENTOR.

M9022]? 1702261221429. BY

"Ml-n u @M w w @w @W ATTORNEY.

1........1 July 11,1939 e i 2,155,39 g

UNITED STATES PATENT OFFICE 'rsrrnvc. momma:

Judson 11. Mansfield, Rockford, 111., minor to Greenlee Bros. & 00.,Rockford, 111.. a corporation of Illinois Application March 15, 1938,Serial No. redo 2s 15 claims, (01. 10-135) More particularly theinvention relates to inroller bearings I] and ID, the pinion being 842-,dividual lead screw tapping spindles o1-v spindle cured against movementlongitudinally of the assemblies, it being the general object of theinbearing by means of a shoulder IS on the pinion vention to provide anew and improved tapping engaging the inner race of bearing l1 and alock 5 spindle of this type. .7 washer 20 which is clamped against theinner Another object is to provide a new and im-' race of bearing I8 bymeans of a nut 2| threaded proved individual lead screw spindle assemblyonto the end of the tubular extension I4. The I which has means yieldingwhen an obstruction is pinion It serves as a drivemeans for the spindleencountered so as to prevent damage to the tap and may, itself, bedriven by a suitable motor and 10 and work, and which automaticallyresets itself gearing (not shown) in a manner well known in 10 whenreversed and withdrawn from the work. the art.

Another object is to provide such a spindle Upon driving the pinion H,the pinion will, assembly which is readily removable from. the throughthe splines I5 and it, drive the spindle head or other machine part inwhich it is sup- I0, and since the splined end of the spindle is 16ported, slidable longitudinally in the pinion and bearing Another objectis to provide such a spindle I3, it is free to move toward the right toengage assembly which can be adjusted from the outside a tap 22 with awork piece (not shown) and to of its supporting head. feed the taprelatively to the work.

Another object is to provide an individual lead In order'to relieve thecutting teeth on the screw tapping spindle assembly of simple contap'from the function of feeding the spindle rel- 20 struction and which isemcient and reliable in atively to the work, the spindle is providedwith operation and readily installed and adjusted. an individual leadscrew 23 which is formed on Further objects will become readily apparentan intermediate portion thereof and engages a from the followingdetailed description, taken in nut 2%. In the form of the inventiondisclosed connection with the accompanying drawing, in herein, the nut24 is normally held against rota- 25 which: tion but is yieldable in adirection away from the Fig. 1 is a vertical section through a spindlework piece in the event the tap encounters an supporting head showing apreferred form of the obstruction. To this end, the nut 24 is providedinvention in elevation. V with a pair of diametrically positionedoutwardly Fig. 2 is a section through the head and spindle extendinglugs 25 which engage in longitudinal 30 along the line 2-2 of Fig. I, aportion being slots 26 formed in a tubular member 21. This shown inelevation for the sake of clearness. member is secured to a reducedportion 28 of the Figs. 3, 4 and 5 are'transverse sections along sleevebearing l3 by meansof a pair of oppothe' lines 3-3, Il-4 and 5-5 of Fig.1, respecsitely disposed screw devices 29 which extend an tively.through a band 30 on the member 21 and into While the invention issusceptible of various threaded engagement with the bearing sleevemodifications and alternative constructions, it is portion 28. The band30 is preferably provided here shown and will hereinafter be describedin for additional strength when the slots 26 extend a. preferredembodiment, but it is not intended to the adjacent end of the member 21and may 40 that the invention is to be limited thereby to the be securedthereto by solder or in any other 40 specific construction disclosed,but it is intended suitable manner. As illustrated herein, the memtocover all modifications and alternative conber 21 is also provided witha pair of diametristructions falling within the spirit and scope ofcally opposite projections 3| which engage in rethe invention as definedby the appended claims. cesses 32 in the main portion of the sleevebear- I In the form chosen for purposes of disclosure, ing l3. v r 45 atapping spindle I0 is rotatably mounted in a The nut 24 is yieldablymounted by means of head orsupport having a forward wall H and an' acoiled spring 33, interposed between the rear inner wall l2, the forwardend of the spindle face 24 of the nut and a ring 34 secured in the beingsupported in a sleeve bearing 13. The rear rear end of the tubularmember 21 by turning the end of the spindle extends through a splinedend inwardly at 35. This spring normally main- 50 bore of a drive pinionI 4 and has splines IS in tains the forward face 24" of the nut inengageslidable and driving engagement with splines l6 ment with the rearend of the bearing sleeve poron the pinion. The pinion has a tubularextention 28 and is sumciently strong to exert the vsion I I which isrotatably supported on the wall pressure necessary to start the tap whenit is fed I2 of the machine head by means of a pair of into the holeusually provided in the work piece. 55

If, however, the tap meets an obstruction, such as a work piece in whichno hole has been drilled, the nut 24 feds backward against the action ofthe spring 33. When the spindle rotation is reversed, the nut movesforward until it abuts the bearing sleeve before the tap and spindle arereturned toward the left (Figs. 1 and 2) so that the individual leadscrew and its nut are automatically reset.

The invention also provides a construction whereby the spindle may beadjusted from externally of the head in which it is mounted and, ifdesired, may readily be removed. In the present form, this isaccomplished by securing the bearing sleeve l3 detachably in the forwardwall ll of the machine head and providing means for rotating this sleevein the head to rotate the lead screw nut 24. Furthermore," the outerdimension of the sleeve I3 is made larger than the band 30 and thetubular member 21, so that the sleeve l3 and theentire spindle assemblymay be drawn out toward the right, disengaging the rear or splined endof the spindle from the pinion l4.

The sleeve 13 is herein provided with a collar portion 36 which abutsagainst the adjacent face of the front wall ll of the machine head andis adapted to be clamped in this position by means of a bifurcated clampmember 31 and a bolt 38 having a nut 39. The lower end of the clampmember has a projecting portion 40 forming a fulcrum, and the legs ofthe member have portions 4! engaging the outer face of the collar 36.The outer end of thebearing sleeve is provided with radially extendingtool receiving slots 42 to facilitate rotating the sleeve when the clampis loose, to adjust the lead screw nut. As shown herein, the bolt 38 isa socket-head type. The nut 39 is preferably secured to the head so asto permit removal of the bolt without dropping the nut.

The tap 22 is herein mounted in the usual holder 43 and secured in atapered bore 44 in the spindle Ill.

The operation 'of the invention is believed readily apparent. With theclamp 31 tightened and the pinion l4 driven (for example, in a clockwisedirection looking at Figs. 3 and 4), the spindle will feed toward theright (Figs. 1 and 2) due to the action of the lead screw. Thelongitudinal movement of the spindle will continue under the control ofthe lead screw until the tap enters the usual drilled hole in the workpiece and commences to cut. The lead screw is provided with the samenumber of threads per inch as the tap, so that the lead screw willcooperate with the tap in determining the feed of the tap into the workand the nut 24 will remain in engagement with the end of the bearingsleeve.

Generally, the work pieces placed in machines of the type underconsideration are first provided with drilled holes properly located, sothat the tap performs no drilling function. If, due to inadvertence orbreakage of a drill in a drilling machine, a particular work piece doesnot have the necessary drilled hole, the tap encounters an obstruction,the nut 24 yields toward the left (Figs. 1 and 2) until the forwardrotation of the spindle and tap ceases. Upon reversal of the spindle andtap, however, the nut moves back to its normal position andautomatically resets the device for the next operation. Since it iscustomary to rotate the pinion l4 in a reverse direction exactly thesame number of revolutions as it is rotated in a forward direction, thetap will be advanced and retracted exactly the same in all successiveoperations. When abnormal obstructions are encountered, the nut yieldstoward the left and prevents damage to the tap 5 and work and stillresets the device automatically upon reversal of the spindle.

The invention provides a simple and readily adjustable spindle assemblyor structure. With the tubular member 21 secured to the hearing n sleeveI3, the two parts form a unitary tubular carrier or supporting structureby which the spindle is rotatably, adjustably and removably mounted onthe machine head. By loosening the clamp 31, the spindle may be adjustedand by re- 15 kind are frequently used in multi-spindle machines havinga large number of taps, the need for a readily removable spindleassembly, and also one which prevents breakage of the tap, will bereadily apparent.

I claim as my invention: 3

1; In a tapping machine, in combination with a support for a tapspindle, a bearing sleeve mounted in a bore in said support, a clampdevice for securing said sleeve in angularly adjusted position to saidsupport, a tap supporting spindle rotatably mounted in said sleeve andhaving one end adapted for connection to a drive means, a lead screw onsaid spindle, a nut for said lead screw, means for securing said nutagainst rotation relative to the lead screw comprising a tubular membersecured at one end to said bearing sleeve and having a longitudinal slotand means on said nut positioned in and movable longitudinally in saidslot, means for normally holding said nut against longitudinal 4,

movement comprising a coil spring surrounding a portion of the spindleand having one end engaging the rear face of the nut, and means on saidtubular member engaging the other end of said spring. 5 2. In a tappingmachine, in combination with a support for a tap spindle, a tubularstructure detachably mounted in a bore in said support, a clamp devicefor securing said structure in angularly adjusted position to saidsupport, a 5 tap supporting spindle rotatably mounted in said structureand having one end adapted for connection to a drive means, a lead screwon said spindle, a nut for said lead screw, means for securing said nutagainst rotation relative to the lead screw comprising a longitudinalslot in said tubular structure and means on said nut movablelongitudinally in said slot, means for normally holding said nut againstlongitudinal movement comprising a coil spring surrounding a portion ofG the spindle and having one end engaging the rear face of the nut, andmeans on said tubular structure engaging the other end of said spring.

arasoo in said slot, and means for normally holding said nut againstlongitudinal movement relatively to said tubular member.

4. In a tapping machine, in combination with a support having outer andinner walls, a drive pinion rotatably mounted on the inner wall, a

bearing sleeve detachably mounted in axial alignment on the outer wall,a spindle rotatably mounted'in said bearing sleeve and having a splinedportion extending into said pinion to be supported and driven thereby, alead screw on said spindle, a nut for said lead screw, means forming anabutment for the forward end 01 the nut to limit its movement in thatdirection, a spring device for maintaining said nut in engagement withsaid abutment and of suflicient strength to cause a tap on the spindleto start cutting a work piece, and means carried by and removable withsaid bearing sleeve for maintaining said spring in compression. M

5. In a tapping machine, in combination with a support having outer andinner walls, a drive pinion rotatably mounted on the inner wall, abearing sleeve mounted in axial alignment on the outer wall, a spindlerotatably mounted in said bearing sleeve and having a portionextend-.ing into said pinion to be supported and driven thereby, a lead screwon said spindle, a nut for said lead screw, means limiting its movementlongitudinally in one direction, a spring device for normallymaintaining said nut at the limit of its movement in said direction, andmeans carried by said bearing sleeve for holding said nut againstrotation and for maintaining said spring in compression.

6. In a tapping machine, in combination with a support having outer andinner walls, a drive pinion rotatably mounted on the inner wall, abearlng sleeve detachably mounted in axial alignment on the outer wall,a spindle rotatably mounted in said bearing sleeve and having a splinedportion extending into said pinion to be supported and driven thereby, alead screw on said spindle, a

nut for said lead screw, and means carried by and removable with saidbearing sleeve for supporting said nut.

'7. In a tapping machine, in combination with a support, a tubularmember having one end mounted on said support, a tap supporting spindlerotatably mounted within said tubular member, a lead screw on saidspindle, a nut for said lead screw movable longitudinally in saidmember, means on said nut and member for preventing rotary movement ofthe nut relatively to the member, while permitting relative longitudinalmovement therebetween, yieldable means carried within said memberadapted normally to resist movement of the nut relatively to the memberin one direction, and a detachable clamping member for clamping saidmember to said support releasable to permit angular adjustmentof saidmember on said support.

8. A tapping machine spindle having, in combination, a tubular memberadapted at one end to be mounted on a support, a tap supporting spindlerotatably mounted within said tubular member, a lead screw on saidspindle, a nut for said lead screw movable longitudinally in saidmember, means on said nut and member for preventing rotary movement ofthe nut relatively to the member, while permitting relative longitudinalmovement therebetween, and yieldable means carried within said memberadapted normally to prevent movement of the nut relatively to the memberin one direction.

9. In a tapping machine, incombination with a support, an elongatedmember having one end mounted on said support, a tap supporting spindlerotatably mounted on said member, a lead screw on said spindle, a nutfor said lead screw movable longitudinally on said member, means on saidnut and member for preventing rotary movement of the nut relatively tothe member, while permitting relative longitudinal movementtherebetween. and

means adapted normally to resist movement of the nut relatively to themember in one direction.

10. In a tapping machine, in combination with a support, a tubularmember having one end mounted on said support, a tap supporting spindlerotatably mounted within said tubular member,

a lead screw on said spindle, a nut for said lead screw movablelongitudinally in said member, means on said nut and member forpreventing rotary movement 01 the nut relatively to the member, and aclamping member for clamping said'tubular member to said supportreleasable to .permit the tubular member and the spindle therein to beremoved from the support.

screw movable longitudinally in said member,

means on said nut and member for preventing rotary movement of the nutrelatively to the member,'while permitting relative longitudinalmovement therebetween in one direction during a tapping operation, andmeans for moving the nut in the opposite direction upon reversal of thespindle.

12. In a tapping machine in combination with a supporting structure, atap supporting spindle rotatably mounted on said supporting structure, alead screw on said spindle, a nut on said lead screw, means forpreventing relative rotary movement between said nut and said supportingstructure while permitting relative longitudinal movement therebetweenin one direction, and yieldable means normally preventing suchlongitudinal movement yieldable in the event the tap encounters anobstruction and operating automatically to return the nut to its normalposition upon reversal of the tap spindle.

13. In a tapping machine in combination with a supporting structure, atap supporting spindle rotatably mounted on said supporting structure, alead screw on said spindle, a nut on said lead screw, means forpreventing relative rotary movement between said nut and said supportingstructure while permitting relative longitudinal move-.

ment therebetween in one direction, and means normally preventing suchlongitudinal movement yieldable in the event the tap encounters anobstruction during forward rotation thereof and operating automaticallyto reset the nut and screw device to their normal position upon reversalof the tap spindle.

14. In a tapping machine in combination with a supporting structure, atap supporting spindle rotatably mounted on said supporting structure, alead screw on said spindle, a nut on said lead screw, and means normallymaintaining said nut stationary on said supporting structure includingyieldable means operable to permit movement of the nut on the supportingstructure in the event the tap encounters an obstruction and operatingautomatically to return the nut to its normal position upon reversal ofthe tap spindle.

1'5. A tapping machine spindle assembly having, in combination, a memberadapted to be mounted on a support, a tap supporting spindle rotatablymounted on said member, a lead screw on said spindle, a nut on said leadscrew movable longitudinally of said member, means on said nut

